New Halo Device Helps in Stroke Treatment

By Liz Caldwell

The ClotBust ER® was developed by William Culp, M.D., professor of radiology, surgery, and neurology and vice chairman of research at UAMS. The device fits on the head like a halo and delivers therapy to quickly bust clots that cause stroke.

Culp has spent many years studying therapy for stroke. One element of Culp’s work included using ultrasound (high-frequency sound waves) in combination with the clot-busting drug tissue plasminogen activator (t-PA).

While looking into the treatment to dissolve clots in blood vessels, Culp realized one problem is getting the ultrasound to operate through the skull. Ultrasound can be delivered anywhere in a patient’s body unless the waves hit something hard like bone or something very soft, like air.

“We realized we had trouble delivering ultrasound to the vessels at the base of the brain,” Culp said. “The skull stopped the ultrasounds.”

Culp and Doug Wilson, assistant director at the Graduate Institute of Technology at the University of Arkansas at Little Rock, teamed up to brainstorm ideas of how to get the ultrasound waves to reach the clot in stroke patients.

Culp received an $8,000 grant from UAMS that provided him with the materials he needed to do experiments. Culp and Wilson completed their first patent for “ultrasound for augmented clot lysis” in 2005. The patent was licensed in 2006 and has been indevelopment by Cerevast Therapeutics since then.

The ClotBust ER® has 16 transducers scattered around the inside – designed to line up with the thin points in the skull: the temples and the foramen magnum in the base of the skull. This allows the ultrasound waves to move through the brain without interruption. After the patient is administered an IV containing t-PA, the circular device is placed onto the patient’s head like a sports visor or halo.

“The idea is to deliver ultrasound wherever the clot is and where the IV t-PA is working,” Culp said. “It makes t-PA work better – improving the clot-busting drug by 40 or 50 percent. It’s like taking a cooking pot and stirring it. The ultrasound stirs the drug around, making it work better.”

The clot disappears more quickly. “If we resupply blood, we resupply oxygen. The brain recovers quicker. Quicker is of course better,” Culp said.

Now in a Phase Three human trial, the ClotBust ER® has been tested in more than 300 patients. None of the results have come back with significant adverse effects. Since the trial periods began, 66 other university sites have signed up to be included in the testing. The device will also soon be available at some sites of the statewide stroke network called AR SAVES while it is in trial.

“Our goal is to test 840 patients,” Culp said. “But right now, the results are looking so promising that it is possible testing could be stopped early if the safety committee determines we don’t have to go any further.”
Culp is hopeful the device will be approved by the start of 2016.

“We’re here to find a cure,” Culp said. “This device is just one part of many things. We mustn’t forget prevention.”

Culp says there has been a significant decrease in strokes nationally and in Arkansas during the past 20 years. This is particularly good news for Arkansas, which ranks highest in the nation for rate of stroke deaths. Culp believes Americans as a whole have a better awareness of the disease.

“But for those 800,000 people who will have a stroke in the United States every year, we still have to have good therapy,” Culp said. “This device may well be the next step.”